Related papers: The Twofold Quasar-galaxy Connection
Quasars (QSOs) hosting supermassive black holes are believed to reside in massive halos harboring galaxy overdensities. However, many observations revealed average or low galaxy densities around $z\gtrsim6$ QSOs. This could be partly…
We consider whether Broad Absorption Line Quasars (BAL QSOs) and Narrow Line Seyfert 1 galaxies (NLS1s) are similar, as suggested by Brandt & Gallagher (2000) and Boroson (2002). For this purpose we constructed a sample of 11 BAL QSOs from…
The presence of supermassive black holes at redshift z > 6 raises some questions about their formation and growth in the early universe. Due to the construction of new telescopes like the ELT to observe and detect SMBHs, it will be useful…
We report on results from H band imaging observations of a complete sample of high-luminosity low-redshift QSOs. The luminosity function of QSO hosts is similar in shape to that of normal galaxies, although offset in normalisation by a…
We report on the current status of our search for protoclusters around quasars at z > 4. While the search is still very incomplete, clustered companion galaxies are found in virtually every case examined so far. The implied comoving number…
One of the key open questions in cosmology today pertains to understanding when, where and how super massive black holes form, while it is clear that mergers likely play a significant role in the growth cycles of black holes, how…
The correlation between the mass of supermassive black holes in galaxy nuclei and the mass of the galaxy spheroids or bulges (or more precisely their central velocity dispersion), suggests a common formation scenario for galaxies and their…
We combine the QSO samples from the 2dF QSO Redshift Survey (2QZ) and the 2dF-SDSS LRG and QSO Survey (2SLAQ) in order to investigate the clustering of z~1.4 QSOs and measure the correlation function. The clustering signal in z-space,…
Understanding the links between the activity of supermassive black holes (SMBH) at the centres of galaxies and their host dark matter haloes is a key question in modern astrophysics. The final data release of the SDSS-IV eBOSS provides the…
Virial black-hole mass estimates are presented for 12698 quasars in the redshift interval 0.1<z<2.1, based on modelling of spectra from the Sloan Digital Sky Survey (SDSS) first data release. The black-hole masses of the SDSS quasars are…
The formation of massive black holes may precede the epoch that characterises the peak of galaxy formation, as characterized by the star formation history in luminous galaxies. Hence protogalactic star formation may be profoundly affected…
Based on the physical model of a supermassive black hole (SMBH) growth via gas accretion in a circumnuclear disk (CND) proposed by Kawakatu & Wada (2008), we describe the formation of high-$z$ ($z > 6$) quasars (QSOs) whose BH masses are…
We examine predictions for the quasar luminosity functions (QLF) and quasar clustering at high redshift (z > 4.75) using MassiveBlack, our new hydrodynamic cosmological simulation which includes a self-consistent model for black hole growth…
Using the modelling code X-CIGALE, we reproduced the SEDs of 1,359 SDSS QSOs within the redshift range 0 < z < 4, for which we have NIR/MIR fluxes with the highest quality and spectral data characterizing their SMBHs. Consistent with a…
We use a semianalytic model of galaxy formation to compare the predictions of two quenching scenarios: halo quenching and black-hole (BH) quenching. After calibrating both models so that they fit the mass function of galaxies, BH quenching…
Gravitational lensing predicts an enhancement of the density of bright, distant QSOs around foreground galaxies. We measure this QSO-galaxy correlation w_qg for two complete samples of radio-loud quasars, the southern 1Jy and Half-Jansky…
This paper explores several simple model variations for the connections among quasars, galaxies, and dark matter halos for redshifts 1 < z < 6. A key component of these models is that we enforce a self-consistent black hole (BH) history by…
This paper argues that there is a large population of dark galaxies which reveals its presence by the gravitational lensing of quasars, and outnumbers normal galaxies by around 3:1. There are 8 double quasars with a separation greater than…
We present multicolour images of the hosts of three z=2 QSOs previously detected in R-band by our group. The luminosities, colours and sizes of the hosts overlap with those of actively star-forming galaxies in the nearby Universe. Radial…
At low redshift, massive black holes are found in the centers of almost all large elliptical galaxies, and also in many lower-mass systems. Their evolution is believed to be inextricably entangled with that of their host galaxies. On the…